Generate multiple coupons

I am wondering if anyone has a great idea (or knows of a mod) that will allow me to generate multiple coupon codes for the same thing.

For example... I need 400 coupons for 50% off of a certain product. They have to be individual, unique codes, 1 use each.

Thanks in advance for your help.

bumping... and adding a question..

Does anyone know if there is a limit to how many coupon codes can be in the system at once?

I would like to know how to do this as well.

even a 'copy' function in the coupon area would be nice, with the ability to change the code...